Using Laser Beat Frequency Techniques: To detect reproducibly the presence of tumor viruses in complex biological fluids; To characterize such viruses by their hydrodynamic and electrophoretic properties in solution under varying chemical conditions; and To develop an additional physical tool for immunological studies on these viruses. Using Laser Raman Spectroscopy: To obtain detailed relationships between nucleic acid structure in solution and basic chemical and species dependent properties, such as base pair distribution; To probe structural modifications of the nucleic acid molecules caused by interaction with proteins; and To study nucleic acid structure in more highly organized tissue fractions, such as chromatin, intact nuclei preparations, and viruses.